CPM Homework Help : CCA2 Problem 7-111

Given that $log_{x} 2 = a$ , $log_{x} 5 = b$ , and $log_{x} 7 = c$ , write expressions using $a,b,\ \text{and/or}\ c$ for each log expression below.

$\log_x10$
Hint (a):
See problem 7-39.

$\log_x49$
Answer (b):
$2c$

$\log_{x} 50$

$\log_x56$
Answer (d):
$3a + c$